Ellipsograph



' Aug. 16, 1932. A RONMNG 1,872,505

ELLIPSOGRAPH Filed April 29, 1929 Patented Aug. 16, 1932.

nnrren STATES ADOLPH noniirne, or iamnnziroms. MINNESOTA ELLIPSOGBAPH Application filed April 29,

This invention relates to draftin ins-truments and the primary object is to provide a simple, practical and highly novel device for describing various sizes and shapes of ellipses. This and incidental objects will be more fully disclosed in the course of the following specification, reference b'eing'made to the accompanying drawing, and the invention will be specifically set forth, as such, in w the appended claims.

In the drawing: Fig. 1 is a side elevation of the instrument showing the position assumed by various parts thereof when in use. 15 Fig. 2 is a sectional plan view on the line 22 in Fig. 1 and showing a completed ellipse as described by the instrument.

Fig. 3 is a fractional detail View showing a modification of a part of the device.

2 Fig. 1. is a detail elevation of a pen unit adapted to be substituted for the pencil lead shown in Fig. 1 when an ellipse is to be drawn or described in ink.

Referring to the drawing by reference 25 characters, 5 and ("3 designate a pair of sharply pointed legs, united at their upper ends, and are preferably spring spread with an adjusting screw 7 to space the leg points as may be desired. The construction thus described so is common to various forms of dividers and compasses now in use, and may, it might be noted, still be used as a divider if occasion should require. I

The upper end of the divider unit carries a spindle pin 8, upon which I rotatably secure a goose-neck bracket 9 having a head or finger grip spindle 10 that is in alignment with and above the pin 8. The member 9 has freedom for a slight sliding movement on the pin 8 and is yieldably held up against the head of the pin by a spring 11.

The bracket 9 is also provided with a depending inclined arm 12, the upper portion of which is spring acting with a tendency to spread the lower end outwardly or away from the legs 5 and 6. The lower end of the arm 12 is formed with a split, integral clamping portion 13, adapted to secure either a lead 14 or the pin 15 of a drafting pen 16. The mem ber 13 is releasably clamped over the elements 1929. Serial No. 1555;957. p p 7 ltor 15,"bya screw 17, to hold them securely in place when the instrument is in use.

NVithinthe-clamp 13 the screw 17.1'otatably carries a small-roller 18 over which pass two adj acent strands of a looped cable 19. The 5; ends of the cable 19 are secured to a traveller 20 mounted for vertical adjustment on a bolt or threaded bar 21. This bar isrotatably secured in bearin'gsl22 of the arm 12, and is provided at its upperend, with a knurled o regulator head 23. The looped end of the cable. 19, which may be made of any suitable flexible material, passes about a pair of guides near the lower endsof the legs 5, 6, and is so held in a stretched or taut condition by the spring action of the arm 12. These guides may be merely smooth channeled sections of the legs proper, as indicated at 2 1', or may comprise small rollers 25 carried by the legs, as shown in Fig. 3. I 7 When the ellipse is to be described the points of the legs 5, 6. are inserted in the paper on a line through the longitudinal axis of the proposed. ellipse and at'equally: spaced distances from the predetermined center 7 thereof. The points. are so held in place by slight downward pressure on the finger piece 10, acting through the resilient spring 11. With the pencil or pen adjusted for-proper drawing :contact with the paperthe knob B0 10 is then rotated, movingthe drawing element away from its initial alignment with the leg points. The result of this action,it will be seen,is to-cause a spreading and con sequent shortening of the cable loop, until theelement has ibeenmoved ninety degrees, or to the top of the ellipse, after which the loop again starts to elongate until the second half of the ellipseis started. It will also U -be seen thatthe size of the ellipse is determined entirely by the length of cable loop employed, adjustment of which is made at 23, and that the length of the ellipse in proportion to its height or width is determined by the spacing of the divider leg points, as determined by regulating the screw 7 In short an ellipse of any style or proportionate dimensions may be described and its size is only limited by the size of the instrument.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims.

Having now therefore fully illustrated and described my invention what I claim to be new and desire to protect by Letters Patent is: a 1. A drafting instrument comprising a device adapted to be held in a relatively stationary position on a surface to be marked, a spindle member rotatably secured to the device, a spring arm extending from the spindle member and for supporting a marker at its outer end, a screw member secured to the arm and having an operating head at its upper end, a flexible guide elementconnecting the arm and the device and having a traveller movable on the screw whereby effective length of the guide may be adjusted by the manipulation of the screw head.

2. A drafting instrument comprising a device adapted to be held in a relatively sta tionary position on a surface to be marked, a spindle member rotatably secured to the device, an arm extending from the spindle for supporting a marker at its outer end, a rotatable screw mounted on the arm but held against longitudinal movement, a traveller on the screw, a flexible element connecting the device and arm for controlling the direction of the latter, said element having both ends attached to said traveller for adjustment thereby, the marker end of said arm having a roller over which both'of said elements pass.

3. Adrafting instrument comprising a device adapted to be held in a relatively stationary position on a surface to be marked, an arm p'ivotally connected at its inner end to the device sothat its outer end may be swung thereabout, a clamp at said outer end for securing a marker, a screw for regulating the clamp, a roller on the screw, a traveller'movable longitudinally of the arm, a flexible element connecting the device and arm for guiding the latter, said element passing over the roller and attaching to the traveller, and a screw device foradjustably regulating the position of the traveller. Signed at 'Minneapo-lis, in the county of Hennepin, and State of Minnesota, this 27th day of April 1929. Y

ADOLPH RUNNING. 

